[GHC] #6084: Add stg_ap_pnnv and related call patterns

[GHC]

#6084: Add stg_ap_pnnv and related call patterns
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    Reporter:  SimonMeier        |       Owner:  simonmar        
        Type:  feature request   |      Status:  new             
    Priority:  normal            |   Milestone:  7.8.1           
   Component:  Runtime System    |     Version:  7.4.1           
    Keywords:                    |          Os:  Unknown/Multiple
Architecture:  Unknown/Multiple  |     Failure:  None/Unknown    
  Difficulty:  Unknown           |    Testcase:                  
   Blockedby:                    |    Blocking:                  
     Related:                    |  
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Comment(by SimonMeier):

 @igloo: I have implemented the unboxed continuation calls in the past and
 I was astonished that they were slower than the boxed versions. I didn't
 know enough about the RTS at that time to understand whats going on. Once
 I read the eval/apply paper and the corresponding GHC sources the slowdown
 was however no longer surprising. Currently, unknown calls to IO functions
 with unboxed arguments are expensive because the 'apply' is executed in a
 one by one fashion. This feature request would change that.

 The change only improves unknown calls with unboxed arguments and a final
 void argument. Attoparsec does not profit, as it does not require side-
 effects. The binary builder could profit, but in its current form it would
 additipnally require the stg_ap_pnnnv and stg_ap_nnnv call patterns.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6084#comment:3>
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